The invention relates to a channel arrangement for discharging molten metal from a smelting furnace.
Discharging molten metal from a smelting furnace, such as a blast furnace or a cupola furnace, is referred to by the technical term "tapping". The liquid metal together with the liquid running slag is guided from the smelting furnace through a channel made of fireproof material. The channel is disposed in a thick lining made of refractory clay brick which is generally referred to as "lining".
The high thermal and mechanical stress caused by the annealing liquid material which is conducted through the channel during the tapping, severely stresses the inner surfaces of the channel. This causes increased wear in the so-called slag zone in the upper region of the channel as well as in the so-called pig-iron zone in the lower region. Hence, the channel has to be replaced according to the severity of the erosion, typically in regular intervals when the sidewalls are eroded by about one half of their thickness.
The channel is then taken out of service and repaired. With conventional methods, the worn-out regions are broken away. This can be done partly with machines, partly manually using jackhammers. Thereafter, the channel is from-stripped from inside and the region to be repaired is filled with a pourable compound of a fireproof material.
Several days, including the time required for the pourable compound to dry, have to be set aside before the furnace can be tapped again. Repairing the channel and removing the material from the channel is labor-intensive and time-consuming. Accordingly, the costs associated with the conventional methods tend to be quite high.